Sound-conveying means for phonographs



Sept. 24,1929,

H; o. DROTNING sourm CONVEYING MEANS FOR PHoNoGRAPHs Filed, Aug. 7, 1928- ATTORNEYS' Patented Sept. 24, 1929 PATENT OFFICE HENRY O. DROTNIN G, OF NEW YORK, N. Y.

SOUND-CONVEYING MEANS FOR PHOII'OGR'APHS` Application led August y7, 1928. Serial No. 298,122.

My invention relates to sound conveying means for phonographs, radio receivers, and the like; and the same has for its object more particularly to provide a simple, eiicient and compact device which may be manufactured and readily assembled at low cost, and which produces a tone of good quality.

Another object of the invention is to provide a device of the character specified in which the same is constructed to occupy a re1- atively constricted space such as in a portable set, without reduction in the tone quality lor intensity of sound produced.

Further, said invention has for its object to provide a device of the character specified in which a partition in the cabinet or casing of the sound producing instrument serves to rigidly support the device and to form therewith the complete sound conveying channel incapable of developing undesirable vibration of the walls thereof. l

Further, said invention has for its object to provide a device of the .character specified in which the member forming the partial f sound conveying channel has a varying crosssectional area following approximately an exponential curve. Further,'said invention has for its object to provide a device of the character specified .in

which the member constituting the partial sound conveying channel is molded to a form following said exponential curve.

Other objects will in part be obvious and'in part be pointed out hereinafter.

To the attainment of the aforesaid Vobjects and ends my inventiony consists in the novel details of construction, and in the' combination, connection and arrangement of parts hereinafter more fully described, and then L0 pointed out in the claims.

In the accompanying drawing:

Fig. 1 is a plan showing one form ofy device constructed according to and embodying my said invention;

L5 Fig. 2 is a section thereof on the line 2-2 at Fig. 1 and l Fig. 3 is a perspective thereof.

Referring to the drawing, I have illustrated the device embodying my invention as in- 0 corporated in a phonograph of the portable which the ed with a type haying a-casing 10, cover 12, a horizontal partition or motor board-14, and a motor 16 secured below the latter for driving the rotatable record support 18. The usual tone arm 2() is pivoted in an opening 22 through the forward portion of the partition 14, and the latter at therear thereof is provided with a relatively enlargedV opening 24 through sound produced issues.

Communication is established between the opening 22 and the opening 24 by means of a sound conveying channel 26 located below the partition 14 and formed in part by the partition 14 and in part by the member 28 secgred'to the partition at the lower side thereo The member 28 is preferably composed of moldable' material, such as fabric impregnatsuitable `plastic substance, vwhichhas qualities suitable forconducting .sound without undesirable vibration ofthe walls thereof. I

The member 28 is readily formed in a mold of predetermined contour, andconsists of a channel formation open at the top as indicated 30, and gradually increasing lin width and depth towards the enlarged end thereof, and the same has a flange portion 32 thereon extending about the opening 30. The flange portion 32 serves for 'securing the member 28 to the lower side of the partition 14 by suitable means, such as the screws or tacks 34 which are disposed uniformly along the member 28 to secure the same to the partition, the two partsvforming a rigid structure reducing apprecier-bly the undesirable vibration characteristic of the ordinary horn which is secured at one or two points only.A

The smaller end portion 36 of the member 28 extends transversely at the rear of the 90 motor 16 and merges With'the longitudinal intermediate portion' 38 thereof, the latter portion terminating in an enlarged Haring end portion 40 in front of the motor register-v ing with the opening 24 in the partition `14. 9FV

The lseveral portions 36, 38, and 40 provide a substantially U-.shaped member having a recess 42 in which the motor 16 is received. y

The successive cross sectional areas of the member 28 as illustrated in Fig. l by the 100 broken lines AA, BB., C C, etc. preferably in .crease with the length" according to an expof 'with the l actual cross sectional area of the l 28 preferably diverge upwardly, and the latrstillen the member 28.

By my invention Iprovide a sound con-v op`ening 24 in the partition 14.,

' The lateral wall portions 44 of the member eral portion40 thereof provides for the expansion of the sound wave as the same approachesthe outlet 24. The wall 46`and the wall 48 of the portion 40 curve rapidlyupwardly for directing the sound wave towards mg cross-sectlonal area open at one side se' vcured to said partition, and forming theref the orifice 24.

The edge of the wall portion 46 comprises a downwardly inclined flange 50 serving together with the' flange 32v i veyoroccupying a small space and producing even better resultsI than those obtained by the ordinaryrelatively larger horns usedin the larger phonographs ofthe nonportabletype.

The member 28 is .readily fabricated, and secured to the motor board 14 through the flange 32 by means disposed along the flange e sothat the vmember is supported entirely by and rigidly anchored to the board 14 to form ingthemotor e It is to be noted that the member 28 is read.

therewith a sound conducting passage having walls not liable to vibrate. j f

Further the shape of the member 28 is such ,as to provide ample length vof passage for the sound while retaining ample room for receivily molded-.of 'a material having acoustical qualitiessuitable for horns, the mold being constructed to produce a member having a channel following an exponential law as above described.- The material of the mem'- ber 28, the mounting-therefor and the shape thereof all cooperate to provide a sound conveying' passage which emits a sound of good qlllality and relatively vhigh intensity, even t ough the restricted space in which the member 28 is disposed necessitates economy in` the length .of the sound conveying passage.

1. A casing, al partition therein having a tone arm opening throughv it, a relatively larger opening in the partition for the egress of sound, a channel member open at oneside secured to one side offsaid partitionv and supported therebyv within thecasing and forming therewith `a sound conveying vpassage increasing. in size from said tone arm opening to said relatively vlarger opening,.

said member having laterally extending end portions providinga space therebetween adapted to receive a motor.

2. A casing,'ay partition therein having a to reinforce and tone arm opening through it, al relatively i larger opening in the partition for the egress offsound, a channel member open at one side secured to one side of said partition and .supported vthereby within thecasing and forming therewith a sound conveying passage increasing exponentiallyin size from said tone arm opening to said relatively larger opening,

said member having laterallyextending end f portions providing a space therebetween. adapted to receive a motor.

' 3. The combination with a casing, anda partition therein having an opening therethrough for entry of sound, and a relatively enlarged opening therethrough in spaced relation to the first opening for the egress 'of f the sound, of a channel. memberoffincreas with a sound conveying passage between said.

'mg width and depth, terminating in laV laterall extending enlarged end portion; said mem er being open 'at one side, and a flange extending along theA edges of 'the opening therein for attachment of the member to the surface of a partition to forman :enclosed sound conveying passage.

5. The combination withY a casing,and a partition therein having a tone arm opening therethrough, and a relatively` enlarged opening therethrough in spaced relation to I the iirst opening, of a channel member of invcreasing cross-sectional area following an exponential law, open at the top, and a flange extending alon vthe opening in said member; said member eing secured by said flange to .one side of said partition 4and rigidly sup'- ported thereby Within the casing and the end portions of said member providing a space therebetween for receiving a motor; andthe exit end of said member forming an openenlarged portion substantially coextensive in area with said largeropeningand registering therewith.

6g A casing, a partition therein having a tone arm opening `through it, a `relatively larger opening in the partition for the egress of sound, a channel member open at one side secured to one side of' said partition. and

forming therewith a sound conveying passage having lateral arms oneof which opens into'the tone arm opening and the other of' which opens into the larger opening.

` 7. The combination with a casing, and a partitionthereinfhaving an opening therethrough for'entry of sound, and a relatively enlarged opening therethrough in spaced relation to the first opening for the egress of' the sound, of a channelmembepf increasing cross-sectional area open at one side, a flange extending about the edge of the member for attaching it to said partition and forming therewith a sound conveying passage between said openings; the larger end of said member having an open portion substantially coeXtensive in area with the larger' openingin said partition and registering therewith.

8. A device of the 'character described comprising a cabinet, a motor board positioned Within said cabinet, said motor board adapted tol form the upper portion of an air column horn.

9`. 'A device of the character described comprising a cabinet, a motor board within said cabinet, and a trough-shaped member associated with said motor b'oard and forming therewith a resonant air column.

In testimony whereof, I have signed my name hereto.

HENRY O. DROTNING. 

